As the magnitude and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is an information handling system. An information handling system (IHS) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the magnitude of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for such systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
In an information handling system (IHS), for example, a computer system using a general purpose, multi-core (e.g., on die Clip MultiProcessing (CMP)) processor and more specifically, a CMP processor and operating system using adaptive power management policies, the processor performance state (P state) adjusts based on demand. As the processor utilization for the IHS decreases, the processor may transition to a lower P state to conserve power. Alternatively, as the processor utilization increases, the processor may transition to a higher P state and may consume more power.
In existing operating systems, a target P state selection is based on the combination of processor utilization and the last selected P state. With a turbo mode (TM) capable processor, at the last selected P state, the processor frequency may increase to a highest frequency available when thermal constraints allow it.
Advanced Configuration and Power Interface (ACPI) is a power management system that allows a computer operating system (OS) to control the amount of power consumed by the processor and peripheral devices of the IHS. In existing ACPI processors which include P state information, each selectable core frequency is represented with corresponding control, status, and latency information. A replacement of the highest frequency of the last selected P state with a TM frequency may result in an increased usage of additional processing power when not needed. This may result in performance degrading caused by P state fluctuations due to unnecessary or early transitions to TM.
Conventional CPU power management algorithms allows the processor to engage in a TM in order to provide better processor performance when a current P state of the processor has reached the peak limit and a current utilization of the processor is also relatively high. The conventional CPU power management algorithm has been shown to be optimal in a majority of processor performance per watt evaluations. However, in many instances, such as in the case of a fully multithreaded processor workload, a drop in calculated performance per power ratio may occur when the processor engages in TM. Thus, a need may exist for methods and systems for improving the calculated processor power management system performance by specifying improved rules for the power management algorithm relating to the timing of the engagement of the TM and thereby enhancing the calculated power efficiency of the entire IHS. The enhanced calculated power efficiency for the IHS may be mayaccomplished by achieving gains in the IHS's SPECPower score for a certain level of power consumption by saving power for a given SPECPower score, or both.